<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>render</title>
    <script src="https://unpkg.com/vue@3/dist/vue.global.js"></script>
</head>
<body>
    <div id="root"></div>
    <script>
        const  app=Vue.createApp({
            data(){
                return{
                  
                }
            },
            template:'<test :level="2"><h1>hellow world</h1></test>'
        })
        app.component( 'test',{
            props:['level'],
            render(){
                const {h}=Vue;
                return h('h'+this.level,{},this.$slots.default())
            },
            // template:`<slot/>`
        })
        app.mount('#root')
    </script>
</body>
</html>